Telephone hand-set with combined transmitter and dial



E, S. MOLARN Feb. 27, 1940.

TELEPHONE HAND-SET WITH COMBINED TRANSMITTER AND DIAL 3 Sheefs-Sheet 1 Filed April 28. 1937 INVENTOR ERNEST -51 M LARIV ATTORNEY Feb. 27, 1940. E. s. McLARN 2,191,993

TELEPHONE HAND-SET WITH COMBINED TRANSMITTER AND DIAL Filed April 28, 1937 3 Sheets-Sheet 2 ATTORN EY Feb. 27, 1940. E. s. McLARN 2,191,993

TELEPHONE HAND-SET WITH COMBINED TRANSMITTER AND DIAL Filed April 28, 1937 3 Sheets-Sheet 3 1 FIGS.

lNVENTOR ERNEST s. mum

BY 5 2 ATTORNEY Patented Feb. 27, 1940 UNITED STATES PATENT OFFICE TELEPHONE HAND-SET WITH COMBINED TRANSMITTER AND DIAL Application April 28, 1937, Serial No. 139,492

3 Claims.

This invention relates to telephone transmitters and pertains more particularly to a handset with combined transmitter and dial.

Telephone apparatus is now well known wherein the receiver and transmitter are combined as one unit and the calling dial for automatic calling is formed as a part of the stand for holding the hand-set. While such arrangements have been found successful in use they are open to the disadvantage that the stand must be so located as to be readily accessible to the user since the dial is located in the stand. For desk use, as a practical matter, this necessitates that the telephone instrument as a whole be made movable so that it can be placed at any desired position on the desk, being for example when not in use, out of the way at one side of the desk and when in use being located at another position which is convenient for the operation of the dial. Movable apparatus of this nature is necessarily subject to breakage danger since it may be pushed off from a table or desk where it is being used on to the floor. It has been proposed heretofore to combine a dial in various ways with a hand-set but such combinations have frequently been bulky, poorly balanced and difficult to use.

It is an object of my invention to provide an improved form of hand-set for automatic telephone use wherein the calling dial is combined with the telephone transmitter in such a way that a very compact structure is obtained which is capable of efficient operation.

More specifically it is an object of my invention to provide a hand-set with a calling dial mechanism arranged concentrically with the variable resistance element or capsule of the transmitter.

The above mentioned and further objects and advantages of my invention and the manner of attaining them will be more fully explained in the following description taken in conjunction with the accompanying drawings.

In the drawings, Fig. 1 illustrates in side elevation and partly in section a combined transmitter and dial constructed in accordance with my invention; Fig. 2 is a plan view showing the position of the dial preferred for greatest convenience; Fig. 3 is a sectional view taken along the section line A-A of Fig. 1; Fig. 4 is a sectional view taken along section line BB of Fig. 1; Fig. 5 is a fragmentary view in side elevation and partly in section of a modified form of device embodying my invention; and Fig. 6 is a view in side elevation illustrating the compact nature of the complete hand-set and stand and showing how this apparatus may be attached to the side of an oflice desk.

Referring more particularly to the drawings, reference numeral I indicates generally a telephone hand-set having a transmitter portion 2 and a receiver portion 3. The transmitter portion comprises a housing 4 which is preferably of insulating material, this serving to enclose a combined transmitter and dial unit 5. This combined unit includes a supporting frame 6 which rests upon a shoulder I of the housing 4 and is held firmly in position by means of a ring 8 which is screw threaded inside the end of the housing 4. This ring carries a number plate 9 and a finger stop ID, the proper angular position of the ring and associated number dial and finger stop being assured by means of a pin and spring (not shown) or any other well known device.

The frame member 6 has a centrally disposed bearing portion I I preferably supported by spokes I2 from the main part of the frame member and within the bearing portion I I is rotatably mounted a hollow shaft I3. This shaft, which is preferably formed by die casting, has at its upper end a flange I4 to which is secured a thimble I5, the two parts being joined for example by means of screws I6. This thimble has a centrally disposed recess II accommodating the transmitter variable resistance element or capsule I8, and pe ripheral flange I9 to which is secured a cap 20. This cap has secured to itsupper face a finger wheel 2| by means of which the cap, thimble I5 and shaft I3 may be rotated.

Transmitter button I8 is preferably of the metallic bellows type forming the subject matter of my copending application Ser. No. 134,044, filed March 31, 1937. This capsule, as described in detail in my copending application, consists of a metallic bellows 22 partially or completely filled with granulated carbon and preferably hermetically sealed. Within the capsule is a first electrode which is connected to a shank or pin 23 which is insulated from the bellows 22 while part or all of the inside surface of the metal bellows serves as the second electrode. The capsule is held in position by means of a nut 24 and is insulated from the thimble I5 by suitable means including a washer of insulating material 25.

Reference numeral 26 indicates the transmitter diaphragm which preferably bears against the end of the transmitter capsule at its center while its outer periphery rests against an embossed ring 21 in the cap 28, the transmitter diaphragm being placed under a slight pressure during the assembly o1 the parts so that during use the diaphragm is always slightly deflected so as to bear-firmly against both the end of the transmitter capsule and the cap.

Fixed to the hollow shaft l3, for example by shrinking or pressing, are gear 23 and impulse cam 29. The former is preferably of brass while the latter is of insulating material. The gear 28 engages with a pinion 30 carried by a shaft 3| which also has mounted thereon a gear 32. The last mentioned gear in turn engages a worm 33 fixed to a shaft 34 which drives a governor mechanism 35 comprising two swing arms 36 which rotate inside of and frictionally engage a friction cup 31. The gear train arrangement for driving the governor as just described is largely conventional. The function of the governor is to cause the finger wheel and-its associated cam member 29 to rotate at a uniform speed to its normal position after having been wound up by the action of the operator in dialing a number. The driving force for returning the finger wheel and associated mechanism to the normal position is derived from a spring 38 which is connected at its outer end to the frame member 6 and at its inner end to the hollow shaft 13.

The impulse cam 29 has a plurality of teeth 39 which upon rotation of the impulse cam intermittently engage with a bell crank element 40 pivotally mounted .on a shaft 4|. This bell crank element is of insulating material and causes the impulsing contacts 42 to open and close during the calling operation. As viewed in Fig. 3 the bell crank rotates a part of a revolution in a clockwise direction and then returns to its initial position thereby engaging the movable spring of the. contact body and opening and closing the contacts. Spring 43 serves to maintain the bell crank 40 in its normal inactive position, as shown in Fig. 3.

Indicated generally at 44 is a pile-up ofcontact springs which complete the electric circuits for the hand-set. The two springs '45.-and 45 serve with the stationary member 41 to short circuit the transmitter and receiver when the impulse cam 29 is in its off normal position. In the normal position the projection 48 carried by the impulse cam contacts with the end of spring 45 and holds the three contact elements mentioned out of engagement with one another. Since the projection 48 has a considerable active length an accidental small rotation of the finger wheel will not cause interruption of a conversation by short circuiting of the transmitter and receiver. T

Reference numerals 49, 58, and 52 indicate contact springs connecting with the contact elements of'the pile-up 44. These cooperate with contact springs 53, 54, 55 and 56, respectively, which are fixed to the housing 4, as shown in Fig. 4. Two additional springs 51 and 58 are furnished which serve to-engage with the pin 23 of the transmitter capsule l8 and with the end of hollow shaft l3, which is connected through the member H with the metal bellows 22 of the capsule I8, thereby providing the second circuit connection for the transmitter capsule.

As already explained hereinbefore, the dialing mechanism and the, transmitter are joined together as a unit, the several parts being carried by the stationary frame element 6. This entire unit may be removed from the hand-set by unscrewing the locking ring 8. In assembling the The locking ring 8 is then screwed into position thereby bringing the contact fingers or springs 49, 50, 5| and 52 into firm engagement with the cooperating fingers 53, 54', 55 and 56, carried by the housing 4. At the same time the pin 23 of the transmitter and the end of the hollow shaft I3 engage with spring fingers 51 and 58, respectively, thereby completing all of the electrical circuits necessary for the operation of the mechanism.

The connecting wires for the receiver 3 of the hand-set are molded into the hand-set itself in the well known way. Any further description of the electric circuits is not thought to be necessary since these circuits function in accordance with the teachings of the prior art.

The instruction card 59 is perforated and likewise the cap 20, so that when the hand-set is used, the subscriber may talk naturally into the transmitter section just as if the dialing mechanism had not been incorporated therewith. The voice waves impinge upon the diaphragm 26 and cause a variation in'the pressure applied to the transmitter capsule l8 thereby causing variable electrical currents to flow. The circuit between the hand-set and the other parts of the subscribers station including the stand are completed by means of an electric cable 68, as shown in Figs. 1 and 4. While the number dial and the finger wheel may be located in any desired angular position with respect to the hand-set preferably the number dial is arranged as in Fig. 2, with zero in line with the axis of the hand-set. This position is preferable since it enables the user to hold the hand-set in a natural position while dialing in the usual way.

Fig. [5 shows a form of construction generally similar to that of Fig. 1 except that the transmitter variable resistance unit I8 is fixed with respect to the frame member 6 and so does not rotate with the shaft l3. Reference numeral 68 indicates a supporting yoke attached to the stationary frame 6. The transmitter element l8 and thimble are fixed .to this yoke by means of a nut 6| and associated screw threaded portion of pin 23. The pin has a reduced diameter at the end thereof forming a shoulder 62 which bears against an insulating bushing 63, thereby holding the transmitter unit firmly, but out of electric contact with the frame 6. The pin forms one circuit connection for the transmitter capsule and insulated wire 84 forming the other connection is carried down through an opening 65 in the pin, and connected to the yoke 60 at 66. The diaphragm 26 is held in position by keeper 61, the cap being independent thereof.

This form of construction eliminates the rotating contacts at 51 and 58 of the structure shown in Fig. 1, which may be an advantage in some cases.

'The form of construction of the hand-set as described hereinabove is'very simple and compact in structure and occupies very little more space, if any, than the ordinary hand-set which does not include a dialing mechanism. Since the dialing mechanism is incorporated in the hand-set the stand for the hand-set can be made considerably smaller since its size need not be proportioned for the enclosure of the dialing mechanism'. As a result an extremely small telephone set is secured. This is brought out by Fig. 6 which illustrates the telephone set applied to the lefthand side of an office desk. The set can be rigidly attached in this manner since, the dialing mechanism being secured to the hand-set itself, it is not necessary for the user to operate a dial on the stand itself. For this reason obviously, the stand may be located in some position where it is out of the way and yet within the reach of a user. Being rigidly secured to a fixed body the telephone set is in less danger of damage. On the other hand, if the telephone set is used in the ordinary way on top of a desk it occupies a very small amount of space and presents a very neat appearance. A further feature is that the stand need not be made very heavy nor be provided with special non-slip material on the base thereof to hold it against the force necessary to manipulate the dial, since the dial is not in the stand but instead in the hand-set, the latter being held in one hand of the subscriber while the finger dial is manipulated by the other hand.

Another important feature of the structure shown in Fig. 1 is that since the transmitter capsule is made to rotate with the finger dial there is less danger of the granulated carbon within the capsule packing so as to reduce the efficiency of operation. The frequent rotation of the finger dial and the capsule causes agitation of the granulated carbon in the capsule whereby the proper looseness of these particles of carbon will be assured.

While I have described particular embodiments of my invention for the purposes of illustration it should be understood that various modifications and adaptations thereof may be made without a departure from the spirit of the invention as set forth in the appended claims.

What I claim is:

1. A telephone instrument comprising an impulsing dial having a hollow rotatable shaft and a sound translating transmitter capsule positioned within said hollow shaft and supported independently thereof.

2. A telephone hand-set comprising a handle, a receiver unit mounted at one end of said handle, a combination unit for transmitting speech and producing signal pulses mounted at the other end of said handle, said combination unit including a rotatable plate having finger holes around its periphery, means for producing impulses in response to rotation and release of said plate and a speech transmitter unit beneath and coaxial with said plate, said plate having a further aperture in its central portion and said speech transmitter being acoustically connected to the front of said plate through said finger holes and also said further aperture.

3. A telephone hand-set comprising a'handle, a receiver unit mounted at one end of said handle, a combination unit for transmitting speech and producing signal pulses mounted at the other end of said handle, said combination unit including a fixed plate, a rotatable plate having finger holes around its periphery coaxial with and spaced above said fixed plate, means for producing impulses in response to rotation and release of said rotatable plate, and a speech transmitter unit beneath said rotatable plate, said combination unit having an acoustic passage from the space between said plates to said speech transmitter unit and being positioned with respect to said receiver so that said plates will lie obliquely opposite the mouth of a user when the hand-set is held in normal position with the receiver against the users ear.

' ERNEST S. McLARN. 

